Throttle for a motor driven hammer mechanism

ABSTRACT

A throttle for a motor driven hammer mechanism has a handle (2) connected to a machine housing (1), a first lever (3) swingably connected to the handle, a second lever (6) swingably connected to the first lever, and a spring (7) arranged between the two levers and a transfer device (4) for transferring the movement of the levers to an operating arm (15) on a speed regulator arranged in the hammer mechanism.

BACKGROUND OF THE INVENTION

The present invention relates to a throttle for a motor driven hammermechanism. More particularly the invention relates to a throttle whichallows a simple control of the rotational speed of the motor duringcollaring.

In prior art motor driven hammer mechanisms one has used a leverconnected with one of the handles for controlling the rotational speedof the motor. This solution works well during drilling when one workswith full motor speed. During collaring, when one works with reducedspeed, the prior art throttle is uncomfortable because the lever shouldbe partly pressed down at the same time as the drilling machine shouldbe guided relative to the surface to be worked on.

SUMMARY OF THE INVENTION

The present invention, which is defined in the subsequent claims, aimsat achieving a throttle where the above mentioned drawbacks have beeneliminated through introduction of an extra lever for reducing therotational speed of the motor during collaring. Because of this theoperator can hold the hammer mechanism in a firm grip for guiding thehammer mechanism efficiently and comfortably over the surface to beworked on.

BRIEF DESCRIPTION OF DRAWINGS

An embodiment of the invention is described below with reference to theaccompanying drawings in which FIG. 1 shows a schematic view of a hammermechanism according to the invention. FIG. 2 shows a section through oneof the handles on the hammer mechanism with the throttle in idleposition. FIG. 3 shows a section through the handle with the throttle infull speed position.

DESCRIPTION OF THE BEST MODES FOR CARRYING OUT THE INVENTION

The hammer mechanism shown in the drawings, which can be a drillingmachine and/or a pavement breaker, comprises a machine housing 1 onwhich two handles 2 are arranged for the handling of the machine. A tool11 is inserted into the machine. During operation a hammer piston 12arranged for movement to-and-fro in the hammer mechanism hits the tool.In one of the handles 2 a throttle is arranged. The throttle comprises afirst lever 3 which through a link 13 is swingably connected to thehandle 2. A second lever 6 is through a link 16 swingably connected tothe first lever 3.

Between the levers a spring 7 is arranged to keep the levers apart.Through this the second lever 6 is swung toward an end position relativeto the first lever 3. This end position is defined by a stop 31 on thefirst lever 3. A transfer device 4 in form of a flexible sleeve and acable 14 arranged therein is arranged to transfer the movement of thesecond lever to an operating arm 15 of a speed regulator 5 associatedwith a motor 20 provided in the machine housing 1. The motor can be acombustion engine. an electric motor. a hydraulic motor or some othersuitable motor. The sleeve is at one end connected with the second lever6 and at the other end with a bracket 19 in the machine housing. Thecable 14 is at one end connected with the handle 2 and at the other endwith the operating arm 15 on the speed regulator 5. Cable and sleevecan, of course, be arranged the other way round, i.e. the cable 14 canbe connected to the second lever 6 and the sleeve to the handle 2. Anadjusting screw 8 is arranged on the second lever 6 for adjustment ofthe maximum swing of the second lever 6 relative to the first lever 3.This swing occurs about the link 16 against the action of the spring 7.

With the levers in the positions shown in FIG. 2 the motor idles. In thepositions shown in FIG. 3 the motor is operating at full speed. Throughpressing down the second lever 6 toward the first lever 3 against theaction of the spring 7 the speed of the motor is decreased to a speedsuitable for collaring. The rotational speed for collaring is adjustedwith the adjusting screw 8. With the throttle according to the inventionone can have the first lever completely pressed down during collaringwhich makes it substantially easier to guide the machine duringcollaring.

I claim:
 1. Throttle for a motor driven hammer mechanism comprising ahandle (2) connected to a machine housing (1), a first lever (3)swingably coupled to said handle, and a transfer device (4) coupled tosaid first lever for transferring movement of the position of said firstlever to a speed regulator (5) for controlling the speed of the motor,wherein a second lever (6) is disposed between said first lever and saidtransfer device for swingably coupling said first lever to said transferdevice, said transfer device (4) being coupled to said second lever (6)for transferring movement of the position of said second lever to saidspeed regulator for controlling the speed of the motor independent ofsaid first lever, and a resilient element (7) is arranged between saidfirst (3) and second (6) levers for swinging said second lever (6)toward an end position (31) relative to said first lever (3). 2.Throttle according to claim 1, comprising adjusting means (8) foradjusting the maximum swing of said second lever (6) relative to saidfirst lever (3).
 3. Throttle according to claim 2, wherein saidadjusting means comprises an adjusting screw (8) arranged on said secondlever (6).
 4. Throttle according to claim 1, wherein said resilientelement comprises a spring.
 5. Throttle according to claim 1, whereinsaid end position (31) is a stop element defined on said first lever(3).
 6. Throttle for a motor driven hammer mechanism comprising a handle(2) connected to a machine housing (1), a first lever (3) swingablycoupled to said handle, and a transfer device (4) coupled to said firstlever for transferring movement of the position of said first lever to aspeed regulator (5) for controlling the speed of the motor, wherein asecond lever (6) is disposed between said first lever and said transferdevice for swingably coupling said first lever to said transfer device,said transfer device (4) being coupled to said second lever (6) fortransferring movement of the position of said second lever to said speedregulator for controlling the speed of the motor independent of saidfirst lever, and a resilient element (7) is arranged between said first(3) and second (6) levers.
 7. Throttle according to claim 6, comprisingadjusting means for adjusting the maximum swing of said second lever (6)relative to said first lever (3).
 8. Throttle according to claim 7,wherein said adjusting means comprises an adjusting screw (8) arrangedon said second lever (6).
 9. Throttle according to claim 6, wherein saidresilient element comprises a spring (7).